The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme
The sensitivity of quantitative precipitation forecasts to various modifications of the Kain-Fritsch (KF) convective parameterization scheme (CPS) is examined for twenty selected cases characterized by intense convective activity and widespread precipitation over Greece, during the warm period of 20...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-05-01
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| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | http://www.nat-hazards-earth-syst-sci.net/11/1327/2011/nhess-11-1327-2011.pdf |
| _version_ | 1818953045800648704 |
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| author | N. Mazarakis V. Kotroni K. Lagouvardos A. A. Argiriou C. J. Anderson |
| author_facet | N. Mazarakis V. Kotroni K. Lagouvardos A. A. Argiriou C. J. Anderson |
| author_sort | N. Mazarakis |
| collection | DOAJ |
| description | The sensitivity of quantitative precipitation forecasts to various modifications of the Kain-Fritsch (KF) convective parameterization scheme (CPS) is examined for twenty selected cases characterized by intense convective activity and widespread precipitation over Greece, during the warm period of 2005–2007. The study is conducted using the MM5 model with a two nested domains strategy, with horizontal grid increments of 24 and 8 km, respectively. Five modifications to the KF CPS, each designed to test the sensitivity of the model to the convective scheme formulation, are discussed. The modifications include: (i) the maximization of the convective scheme precipitation efficiency, (ii) the change of the convective time step, (iii) the forcing of the convective scheme to produce more/less cloud material, (iv) changes to the trigger function and (v) the alteration of the vertical profile of updraft mass flux detrainment. <br><br> The simulated precipitation from the 8-km grid is verified against raingauge measurements. Although skill scores vary widely among the cases and the precipitation thresholds, model results using the modifications of the convective scheme show improvements in 6-h precipitation totals compared to simulations generated using the unmodified convective scheme. In general, forcing the model to produce less cloud material improves the precipitation forecast for the moderate and high precipitation amounts, while the same modification and the change of the convective time step to 1 min has the same result for the high precipitation thresholds. The increase of convective time step to 15 min, the maximization of precipitation efficiency and the changes to the trigger function give similar results for medium and high precipitation. On the other hand, the forecast for the light precipitation is improved by forcing the model to produce more cloud material as well as by the alteration of the vertical profile of updraft mass flux detrainment. |
| first_indexed | 2024-12-20T10:00:02Z |
| format | Article |
| id | doaj.art-71c75e2687d84d37b405011c36144051 |
| institution | Directory Open Access Journal |
| issn | 1561-8633 1684-9981 |
| language | English |
| last_indexed | 2024-12-20T10:00:02Z |
| publishDate | 2011-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Natural Hazards and Earth System Sciences |
| spelling | doaj.art-71c75e2687d84d37b405011c361440512022-12-21T19:44:22ZengCopernicus PublicationsNatural Hazards and Earth System Sciences1561-86331684-99812011-05-011151327133910.5194/nhess-11-1327-2011The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization schemeN. MazarakisV. KotroniK. LagouvardosA. A. ArgiriouC. J. AndersonThe sensitivity of quantitative precipitation forecasts to various modifications of the Kain-Fritsch (KF) convective parameterization scheme (CPS) is examined for twenty selected cases characterized by intense convective activity and widespread precipitation over Greece, during the warm period of 2005–2007. The study is conducted using the MM5 model with a two nested domains strategy, with horizontal grid increments of 24 and 8 km, respectively. Five modifications to the KF CPS, each designed to test the sensitivity of the model to the convective scheme formulation, are discussed. The modifications include: (i) the maximization of the convective scheme precipitation efficiency, (ii) the change of the convective time step, (iii) the forcing of the convective scheme to produce more/less cloud material, (iv) changes to the trigger function and (v) the alteration of the vertical profile of updraft mass flux detrainment. <br><br> The simulated precipitation from the 8-km grid is verified against raingauge measurements. Although skill scores vary widely among the cases and the precipitation thresholds, model results using the modifications of the convective scheme show improvements in 6-h precipitation totals compared to simulations generated using the unmodified convective scheme. In general, forcing the model to produce less cloud material improves the precipitation forecast for the moderate and high precipitation amounts, while the same modification and the change of the convective time step to 1 min has the same result for the high precipitation thresholds. The increase of convective time step to 15 min, the maximization of precipitation efficiency and the changes to the trigger function give similar results for medium and high precipitation. On the other hand, the forecast for the light precipitation is improved by forcing the model to produce more cloud material as well as by the alteration of the vertical profile of updraft mass flux detrainment.http://www.nat-hazards-earth-syst-sci.net/11/1327/2011/nhess-11-1327-2011.pdf |
| spellingShingle | N. Mazarakis V. Kotroni K. Lagouvardos A. A. Argiriou C. J. Anderson The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme Natural Hazards and Earth System Sciences |
| title | The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme |
| title_full | The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme |
| title_fullStr | The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme |
| title_full_unstemmed | The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme |
| title_short | The sensitivity of warm period precipitation forecasts to various modifications of the Kain-Fritsch Convective Parameterization scheme |
| title_sort | sensitivity of warm period precipitation forecasts to various modifications of the kain fritsch convective parameterization scheme |
| url | http://www.nat-hazards-earth-syst-sci.net/11/1327/2011/nhess-11-1327-2011.pdf |
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